LUSAKA (Reuters) - Zambia's High Court has rejected an application by the main opposition party to block President Edgar Lungu's inauguration set for next week after last month's contested election, his lawyers said on Friday.

Opposition United Party for National Development (UPND) leader Hakainde Hichilema had petitioned the court to overturn a Constitutional Court decision not to give him more time to legally challenge Lungu's re-election.

He says the Aug. 11 vote was rigged, a charge Lungu denies.

"The court has refused to block the inauguration. The High Court has no power to block a decision of a higher court," Lungu's lawyer Tutwa Ngulube told reporters.

Hichilema's lawyer Keith Mweemba said the UPND would pursue the case in the Supreme Court.

Lungu has led the ruling Patriotic Front since his predecessor Michael Sata died in 2014. He won the presidency in January 2015, defeating Hichilema in their first election confrontation.

Zambia is Africa's second-largest copper producer, but its economy has been hit by a slump in commodity prices, leading to mine closures and exacerbating its already high unemployment.